1. Field of the Invention
The present invention relates to a magnetic random access memory having a magnetoresistive element.
2. Description of the Related Art
In recent years, magnetic random access memories (MRAMs) using the tunnel magnetoresistive (TMR) effect have been proposed as a type of semiconductor memory.
A memory cell of the magnetic random access memory comprises a magnetic tunnel junction (MTJ) element which has a fixed layer, recording layer, and tunnel barrier layer sandwiched between them. It has been found as a result of examination of the MTJ element that the asteroid characteristic can be improved by widening the planar shape of the MTJ element in the hard- and easy-axis directions, i.e., by forming a cross-shaped MTJ element.
However, it is difficult to actually form a cross-shaped MTJ element by processes for mass production. For example, the MTJ element is processed in two steps by using two masks M1 and M2, i.e., the mask M1 which runs in the easy-axis direction (long-axis direction of the MTJ element) and the mask M2 which runs in the hard-axis direction (short-axis direction of the MTJ element). However, when the shapes of the two masks M1 and M2 are simply superposed, the margin for misalignment in the hard-axis direction is small, and the desired asteroid characteristic can not be obtained.
It is an object of the present invention to provide a magnetic random access memory which can suppress misalignment of a portion projecting in the easy-axis direction and improve the asteroid characteristic in a so-called cross-shaped magnetic recording element.